“…Figure 1 shows representative modelling results for the thermo-chemical coal conversion within the raceway zone for temperatures (a), heating rates (b), velocities (c), and particle conversion characteristics (d) versus particle residence time [16, 17]. Hot blast and coal temperatures are around 1250 and 200C at the coal injection point.…”
Section: Defining Raceway Conditionsmentioning
confidence: 99%
“…The particle mass loss curve shows that only around 50% of the particle mass has been converted after 100 ms. However, volatile and char fractions indicate that only pyrolysis char enters the dense coke bed. Figure 1. Typical simulation results for temperature (a), heating rate (b), velocity (c), and thermo-chemical conversion (d) profiles of pulverised coal injected into the blast furnace raceway zone [16, 17]. …”
Section: Defining Raceway Conditionsmentioning
confidence: 99%
“…Typical simulation results for temperature (a), heating rate (b), velocity (c), and thermo-chemical conversion (d) profiles of pulverised coal injected into the blast furnace raceway zone [16, 17]. …”
Section: Defining Raceway Conditionsmentioning
confidence: 99%
“…PC heating rates range between and K/s in the blast furnace raceway [16, 17]. Two distinct coal conversion effects can be associated with high heating rates: particle fragmentation [9–14] and an increased conversion/reactivity of inertinite [7, 19–21].…”
Identifying coals suitable for blast furnace injection has become increasingly important due to rising injection rates. This review of traditional pulverised coal reactivity testing equipment reveals that no agreed-upon evaluation standard exists and that different reactor types are employed for testing. Therefore, reference blast furnace conversion conditions are defined, followed by a discussion of their influence on the coal conversion process as illustrated by conceptual conversion models. Critical process parameters are temperature, heating rate and pressure, while other effects can be calibrated. Evaluating the currently employed test equipment with regard to these process parameters shows that only specially designed drop-tube furnaces and flow reactors provide conversion conditions near to blast furnace conditions. For consistent injection coal testing, special reactors complying with the previously defined critical process parameters must be established.
“…Figure 1 shows representative modelling results for the thermo-chemical coal conversion within the raceway zone for temperatures (a), heating rates (b), velocities (c), and particle conversion characteristics (d) versus particle residence time [16, 17]. Hot blast and coal temperatures are around 1250 and 200C at the coal injection point.…”
Section: Defining Raceway Conditionsmentioning
confidence: 99%
“…The particle mass loss curve shows that only around 50% of the particle mass has been converted after 100 ms. However, volatile and char fractions indicate that only pyrolysis char enters the dense coke bed. Figure 1. Typical simulation results for temperature (a), heating rate (b), velocity (c), and thermo-chemical conversion (d) profiles of pulverised coal injected into the blast furnace raceway zone [16, 17]. …”
Section: Defining Raceway Conditionsmentioning
confidence: 99%
“…Typical simulation results for temperature (a), heating rate (b), velocity (c), and thermo-chemical conversion (d) profiles of pulverised coal injected into the blast furnace raceway zone [16, 17]. …”
Section: Defining Raceway Conditionsmentioning
confidence: 99%
“…PC heating rates range between and K/s in the blast furnace raceway [16, 17]. Two distinct coal conversion effects can be associated with high heating rates: particle fragmentation [9–14] and an increased conversion/reactivity of inertinite [7, 19–21].…”
Identifying coals suitable for blast furnace injection has become increasingly important due to rising injection rates. This review of traditional pulverised coal reactivity testing equipment reveals that no agreed-upon evaluation standard exists and that different reactor types are employed for testing. Therefore, reference blast furnace conversion conditions are defined, followed by a discussion of their influence on the coal conversion process as illustrated by conceptual conversion models. Critical process parameters are temperature, heating rate and pressure, while other effects can be calibrated. Evaluating the currently employed test equipment with regard to these process parameters shows that only specially designed drop-tube furnaces and flow reactors provide conversion conditions near to blast furnace conditions. For consistent injection coal testing, special reactors complying with the previously defined critical process parameters must be established.
“…Since the 1970s, intensive work has been done to develop static and dynamic BF models based on mass and heat balances in the BF from 1-dimensional (1-D) model proposed by Yagi et al [22] to 2-D model, 3-D model, and 3-D unsteady state models [23,24]. Recently, multi-dimensional (2D and 3D) and multi-phase (4, 5 and 6 phases) mathematical models based on chemical kinetics and transport phenomena have been greatly developed to evaluate the effect of injections (e.g., pulverized coal, natural gas, coke oven gas and waste plastics) and innovative burden materials (e.g., carbon composite agglomerate) on the BF performance [25][26][27][28][29]. The growing size of the BFs and the urgent need to follow the burden distribution and analysing the complicated heterogeneous interactions in the furnace, advanced models based on Discrete Element Method (DEM) [30], Computational Fluid Dynamics (CFD) [31] and DEM-CFD [32] are being developed and validated with experimental data.…”
Most modern blast furnaces (BFs) operate with Pulverized Coal Injection (PCI), but renewable and carbon neutral biochar could be applied to reduce the fossil CO2 emission in the short term. In the present study, heat and mass balance-based model (MASMOD) is applied to evaluate the potential of biochar in partial and full replacement of injected pulverized coal (PC) in the ironmaking BF. The impact of biochar injection on the raceway adiabatic flame temperature (RAFT) and top gas temperature (TGT) is evaluated. Three grades of biochar, produced from the pyrolysis of sawdust, were evaluated in this study. The total carbon content was 79.2%, 93.4% and 89.2% in biochar 1, 2 and 3, respectively, while it was 81.6% in the reference PC. For each type of biochar, 6 cases were designed at different injection levels from 30 kg/tHM up to 143 kg/tHM, which represent 100% replacement of PC in the applied case, while the top charged coke is fixed in all cases as reference. The oxygen enrichment, RAFT, and TGT are fixed for certain cases, and have been calculated by MASMOD in other cases to identify the optimum level of biochar injection. The MASMOD calculation showed that as the injection rate of biochar 1 and biochar 2 increased, the RAFT increased by ~190 °C, while TGT decreased by ~45 °C at 100% replacement of PC with biochar. By optimizing the moisture content of biochar and the oxygen enrichment in the blast, it is possible to reach 100% replacement of PC without much affecting the RAFT and TGT. Biochar 3 was able to replace 100% of PC without deteriorating the RAFT or TGT.
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